The Bone-Chilling Freezer Where 10 Miles of Ancient Ice Core Samples are Kept

Since 1993 the United States Geological Survey (USGS) has been extracting ice cores from glaciated regions of the world and storing them for research. Scientists keep them in a gigantic walk-in freezer—the National Ice Core Laboratory—located just outside Denver. It's incredibly cool.

The cores are collected from various parts of Antarctica, Greenland, and North America to study climactic variations. Think of it as drilling down through layers of snow that accumulated year after year which eventually became compacted and turned into ice.

The ice is not just cold, but old as well: Some of it was formed 40,000 years ago. The freezer is 55,000 cubic feet and kept at the delightful temperature of -40°F (-40°C), which according to your tour host David Rees, makes it feel like your face is burning off.

This tour comes courtesy of the National Geographic show Going Deep with David Rees, which premieres tonight as a weekly quest to re-learn seemingly mundane activities we confront in our daily lives, from tying shoelaces to opening doors. In addition, every episode features an infographic distilling the key takeaways from Rees's research. So, for example, his journey to the ice core freezer results in a how-to for making your own perfect ice cubes at home. Hopefully it doesn't take 40,000 years. [Going Deep with David Rees]